Emergence of an extended-spectrum ß-lactamase-producing serotype K1 Klebsiella pneumoniae ST23 strain from Asian countries.

Extended-spectrum ß-lactamase (ESBL) production has been very rare in serotype K1 Klebsiella pneumoniae ST23 strains, which are well-known invasive community strains. Among 92 ESBL-producing strains identified in 218 isolates from nine Asian countries, serotype K1 K. pneumoniae strains were screened. Two ESBL-producing K. pneumoniae isolates from Singapore and Indonesia were determined to be serotype K1 and ST23. Their plasmids, which contain CTX-M-15 genes, are transferable rendering the effective transfer of ESBL resistance plasmids to other organisms.

Predictors of uropathogens other than Escherichia coli in patients with community-onset acute pyelonephritis.

AIM: A constant reduction in the incidence of community-onset acute pyelonephritis (CO-APN) caused by Escherichia coli has been shown with a parallel increase incidence caused by other organisms. Therefore, we evaluated the risk factors and outcome of non-E. coli as uropathogens in patients with community-onset APN. METHODS: As a part of a nationwide multicentre surveillance study conducted in Korea, a total of 416 patients with CO-APN were collected with their epidemiological, antibiotic treatment and outcome data. RESULTS: The risk factors and outcomes of non-E. coli as uropathogens were evaluated in a total of 416 patients with culture-confirmed CO-APN. Non-E. coli caused 127 cases (30.5%) of CO-APN. CO-APN caused by non-E. coli resulted in higher inappropriate empirical therapy (38.6% vs. 20.1%, p < 0.001), longer hospital stay (12.6 days vs. 6.7 days, p = 0.005) and higher 30-day mortality (9.4% vs. 3.8% p = 0.020) compared with CO-APN caused by E. coli. Multivariate analyses showed that male gender (OR, 3.48; CI, 2.13-5.67; p < 0.001), underlying haematological disease (OR, 5.32; CI, 1.17-24.254; p = 0.031), underlying benign prostate hyperplasia (OR, 2.61; CI, 1.02-6.74; p = 0.046), chronic indwelling urethral catheter (OR, 6.34; CI, 1.26-31.84; p = 0.025) and admission history in the previous 6 months (OR, 2.12; CI, 1.23-3.58; p = 0.005) were predictors for CO-APN caused by a non-E. coli isolate. CONCLUSIONS: Community-onset APN caused by non-E. coli represents a distinct subset of urinary tract infections with worse outcomes. The defined risk factors related with non-E. coli should be taken into consideration when empirical antibiotic therapy is prescribed in patients with community-onset APN.

Mitochondrial modulation decreases the bortezomib-resistance in multiple myeloma cells.

Multiple myeloma (MM) is an incurable hematological malignancy that causes most patients to eventually relapse and die from their disease. The 20S proteasome inhibitor bortezomib has emerged as an effective drug for MM treatment; however, intrinsic and acquired resistance to bortezomib has already been observed in MM patients. We evaluated the involvement of mitochondria in resistance to bortezomib-induced cell death in two different MM cell lines (bortezomib-resistant KMS20 cells and bortezomib-sensitive KMS28BM cells). Indices of mitochondrial function, including membrane potential, oxygen consumption rate and adenosine-5'-triphosphate and mitochondrial Ca(2+) concentrations, were positively correlated with drug resistance of KMS cell lines. Mitochondrial genes including CYPD, SOD2 and MCU were differentially expressed in KMS cells. Thus, changes in the expression of these genes lead to changes in mitochondrial activity and in bortezomib susceptibility or resistance, and their combined effect contributes to differential sensitivity or resistance of MM cells to bortezomib. In support of this finding, coadministration of bortezomib and 2-methoxyestradiol, a SOD inhibitor, rendered KMS20 cells sensitive to apoptosis. Our results provide new insight into therapeutic modalities for MM patients. Studying mitochondrial activity and specific mitochondrial gene expression in fresh MM specimens might help predict resistance to proapoptotic chemotherapies and inform clinical decision-making.

Prevalence and clinical characteristics of diabetic peripheral neuropathy in hospital patients with Type 2 diabetes in Korea.

AIMS: Diabetic peripheral neuropathy is a common complication of diabetes. This cross-sectional study investigated the prevalence and clinical characteristics of this neuropathy in patients with Type 2 diabetic mellitus treated at hospitals in Korea. METHODS: Questionnaires and medical records were used to collect data on 4000 patients with Type 2 diabetes from the diabetes clinics of 40 hospitals throughout Korea. Diabetic peripheral neuropathy was diagnosed based on a review of medical records or using the Michigan Neuropathy Screening Instrument score and monofilament test. RESULTS: The prevalence of neuropathy was 33.5% (n = 1338). Multivariate analysis revealed that age, female sex, diabetes duration, lower glycated haemoglobin, treatment with oral hypoglycaemic agents or insulin, presence of retinopathy, history of cerebrovascular or peripheral arterial disease, presence of hypertension or dyslipidaemia, and history of foot ulcer were independently associated with diabetic peripheral neuropathy. Of the patients with neuropathy, 69.8% were treated for the condition and only 12.6% were aware of their neuropathy. CONCLUSION: There was a high prevalence of peripheral neuropathy in patients with Type 2 diabetes in Korea and those patients were far more likely to have complications or co-morbidities. The proper management of diabetic peripheral neuropathy deserves attention from clinicians to ensure better management of diabetes in Korea.

Fecal carriage of serotype K1 Klebsiella pneumoniae ST23 strains closely related to liver abscess isolates in Koreans living in Korea.

We determined the fecal carriage rate of serotype K1 Klebsiella pneumoniae in healthy Koreans and studied their genetic relationship with liver abscess isolates. We compared the carriage according to the country of residence. The stool specimens were collected through health promotion programs in Korea. K. pneumoniae strains were selected and tested for K1 by PCR. Serotype K1 isolates were characterized by multilocus sequence typing and pulsed field gel electrophoresis. A total of 248 K. pneumoniae isolates were obtained from 1,174 Koreans. Serotype K1 was identified in 57 (4.9%), of which 54 (94.7%) were ST 23 and were closely related to the liver abscess isolates. Participants aged >25 years showed a higher fecal carriage rate than those ≤ 25 (P = 0.007). The proportion of serotype K1 out of K. pneumoniae isolates in foreigners of Korean ethnicity who had lived in other countries was lower compared with those who had lived in Korea (5.6% vs 24.1%, P = 0.024). A substantial proportion of Koreans >25 years carries serotype K1 K. pneumoniae ST23 strains, which are closely related to liver abscess isolates. Differences in carriage rates by country of residence suggests that environmental factors might play an important role in the carriage of this strain.

Four cases of possible human infections with Delftia lacustris.

We report four cases of possible human infections with Delftia lacustris. D. lacustris isolates, which were isolated from blood cultures and bile fluid of patients with underlying diseases such as empyema, renal injury, hepatocellular carcinoma, and renal infarction, were identified using 16S rRNA gene sequencing and biochemical tests. Four D. lacustris isolates did not show the same antimicrobial susceptibility profiles and enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) patterns, indicating their non-clonality.

A decision tree-based approach for identifying urban-rural differences in metabolic syndrome risk factors in the adult Korean population.

AIM: The purpose of this study was to explore the difference in the pattern of metabolic syndrome (MetS) in urban and rural populations in Korea using data mining techniques. SUBJECTS AND METHODS: In total, 1013 adults >30 yr of age from urban (184 males and 313 females) and rural districts (211 males and 305 females) were recruited from Gyeongsangnam-do, Korea. Modified National Cholesterol Education Program Adult Treatment Panel III criteria were used to identify individuals with MetS. We applied a decision tree analysis to elucidate the differences in the clustering of MetS components between the urban and rural populations. RESULTS: The prevalence of MetS was 33.2% and 35.2% in urban and rural districts, respectively (p=0.598). The decision-tree approach revealed that the combination of high serum triglycerides (TG) + high systolic blood pressure (SBP), high TG + low HDL cholesterol, and high waist circumference (WC) + high SBP + high fasting plasma glucose (FPG) were strong predictors of MetS in the urban population, whereas the combination of TG + SBP + WC and SBP + WC + FPG showed high positive predictive value for the presence of MetS in the rural population. CONCLUSIONS: Although no significant difference was found for the prevalence of MetS between the two populations, the differences in the clustering pattern of MetS components in urban and rural districts in Korea were identified by decision tree analysis. Our findings may serve as a basis to design necessary population-based intervention programs for prevention and progression of MetS and its complications in Korea.

Comparison of the efficacy and safety of tramadol/acetaminophen combination therapy and gabapentin in the treatment of painful diabetic neuropathy.

AIMS: This study compared the efficacy and safety of tramadol/acetaminophen (T/A) and gabapentin in the management of painful diabetic neuropathy. METHODS: An open, randomized, comparative study was conducted. Subjects with painful symmetric neuropathy in the lower limbs and mean pain-intensity score > or = 4 on a numeric rating scale were eligible. Subjects were randomized to receive either tramadol (37.5 mg)/acetaminophen (325 mg) or gabapentin (300 mg) for 6 weeks. After 2 weeks of the titration period (1200 mg/day for gabapentin and three tablets/day for T/A), the doses were maintained if the pain was relieved. The primary efficacy outcome was a reduction in pain intensity. Secondary measures evaluated a pain relief scale, a Brief Pain Inventory, a 36-item Short Form Health Survey, average pain intensity and sleep disturbance. RESULTS: One hundred and sixty-three subjects (T/A 79; gabapentin 84) were included. At the final visit, the mean doses were 1575 mg/day for gabapentin and 4.22 tablets/day for T/A. Both groups were similar in terms of baseline pain intensity (mean intensity: T/A 6.7 +/- 1.6; gabapentin 6.3 +/- 1.6, P = 0.168). At the final visit, the mean reductions in pain intensity were similar in both groups (T/A -3.1 +/- 2.0; gabapentin -2.7 +/- 2.1, P = 0.744). Both groups had similar improvements in every Short Form Health Survey category and Brief Pain Inventory subcategory, and in the mean pain relief scores. CONCLUSION: This study suggests that the T/A combination treatment is as effective as gabapentin in the treatment of painful diabetic neuropathy in patients with Type 2 diabetes.

Conditions required for the stimulation of bioluminescence activity of the genetically engineered bacteria, P. putida mt-2 KG1206, preserved by deep-freezing.

Herein the conditions required for the stimulation of bioluminescence activity in a genetically engineered strain of Pseudomonas putida mt-2 KG1206, containing the intact TOL plasmid and a constructed plasmid with the P(m)-lux gene, are reported upon. Both sodium lactate (SL) and potassium nitrate (KNO(3)) were able to stimulate the bioluminescence activity, but a greater increase was observed with nitrogen amendment. This selected stimulant was then tested on reconstituted cells that had been preserved by deep-freezing and mixed with pure inducer solution or groundwater samples. The stimulation of bioluminescence activities for deep-frozen strain was in the range of 101-238% of the control. The effect of KNO(3) was found to be dependent on the type of inducers used and the cell conditions. In general, high bioluminescence activity was observed with groundwater samples, contaminated with high inducer compounds. However, no significant correlation was observed between the bioluminescence intensity and the total inducer concentration in the environmental samples contaminated with complex mixtures with inducers. These results should be useful when other recombinant bioluminescence strains are to be used for environmental monitoring. Overall, the results of this study demonstrate the stimulant conditions for the bioluminescence activity of genetically engineered bacteria, and suggest the potential for preliminary application of this deep-frozen engineered strain in a field-ready bioassay to conveniently detect or monitor a specific group of environmental contaminants.

Lytic transglycosylase contributes to the survival of lipooligosaccharide-deficient, colistin-dependent Acinetobacter baumannii.

OBJECTIVES: The phenomenon of colistin dependence in Acinetobacter baumannii has been described in a situation in which colistin is now considered as the last resort for the treatment of infections caused by multidrug-resistant Gram-negative bacteria. In this study, we aimed to reveal a gene associated with colistin dependence in A. baumannii. METHODS: The colistin-dependent A. baumannii H08-391D strain was isolated from a patient, and target gene-inactivation mutants were constructed. We investigated the effects of target gene on colistin dependence with quantitative real-time PCR and endotoxin assay. Also, we observed the change of cell morphology by electron microscopy. RESULTS: The expression of ACICU_02898, encoding a soluble lytic transglycosylase associated with cell-wall degradation and recycling, was increased by eight-to 42-fold in colistin-dependent mutants, and deletion of ACICU_02898 in a colistin-dependent strain led to colistin susceptibility (MIC = 8 mg/L). Endotoxin activity was significantly low in a colistin-dependent derivative ACICU_02898-inactivated mutant and a complemented mutant. In addition, the ACICU_02898-inactivated mutant showed a highly reduced growth rate. The colistin-dependent derivative and ACICU_02898-inactivated mutant showed clearly distinguished absorption profiles in the red/green fluorescence dot blot with regard to their membrane potential. Electron microscopy revealed that the deletion mutant cells were elongated compared to the colistin-susceptible wild-type strain and colistin-dependent strain. CONCLUSIONS: A colistin-dependent A. baumannii strain exhibited a deficiency in its outer membrane integrity and high expression of lytic transglycosylase was required for survival. This study reveals why the colistin-dependent mutant can tolerate high antibiotic concentrations.

Inappropriate initial antimicrobial therapy as a risk factor for mortality in patients with community-onset Pseudomonas aeruginosa bacteraemia.

This study was performed to identify the risk factors for mortality and evaluate the effect of inappropriate initial antimicrobial therapy on the outcomes of patients with community-onset Pseudomonas aeruginosa bacteraemia in an emergency department (ER) setting. All cases with P. aeruginosa bacteraemia occurring within 48 h after ER visit from January 2000 to December 2005 were retrospectively analysed. A total of 106 community-onset P. aeruginosa bacteraemia cases in the ER were included (mean age, 57.61 +/- 14.44 years old; M:F, 58:48). Although P. aeruginosa bacteraemia was diagnosed in the ER, most of the cases of P. aeruginosa bacteraemia were healthcare-associated (88.7%). Malignancy (n = 83, 78.3%) was the most common underlying disorder. Fifty patients (47.2%) were neutropaenic and 56 patients (52.8%) had septic shock. The overall 30-day mortality rate was 26.4% (28/106). In the univariate analysis, underlying malignancy, high Charlson's weighted index of comorbidity (> or = 3), high Pitt bacteraemia score (> or = 4), indwelling central venous catheter and inappropriate initial therapy were significantly associated with 30-day mortality (all P < 0.05). In the multivariate analysis, high Pitt bacteraemia score (OR, 17.03; 95% CI, 4.60-63.15; P < 0.001) and inappropriate initial antimicrobial therapy (OR, 4.29; 95% CI, 1.39-13.24; P = 0.011) were found to be significant risk factors for 30-day mortality. The 30-day mortality rate was significantly higher in the inappropriate therapy group (18/51, 35.3%) than in the appropriate therapy group (10/55, 18.2%) (P = 0.046). This study demonstrated that inappropriate initial antimicrobial therapy was significantly associated with unfavourable outcomes in patients with community-onset P. aeruginosa bacteraemia. As P. aeruginosa bacteraemia can be a fatal infection, even when community-onset, inappropriate antimicrobial therapy should be avoided in suspected cases of P. aeruginosa bacteraemia.

RNA polymerase beta-subunit gene (rpoB) sequence analysis for the identification of Bacteroides spp.

Partial rpoB sequences (317 bp) of 11 species of Bacteroides, two Porphyromonas spp. and two Prevotella spp. were compared to delineate the genetic relationships among Bacteroides and closely related anaerobic species. The high level of inter-species sequence dissimilarities (7.6-20.8%) allowed the various Bacteroides spp. to be distinguished. The position of the Bacteroides distasonis and Bacteriodes merdae cluster in the rpoB tree was different from the position in the 16S rRNA gene tree. Based on rpoB sequence similarity and clustering in the rpoB tree, it was possible to correctly re-identify 80 clinical isolates of Bacteroides. In addition to two subgroups, cfiA-negative (division I) and cfiA-positive (division II), of Bacteroides fragilis isolates, two distinct subgroups were also found among Bacteroides ovatus and Bacteroides thetaiotaomicron isolates. Bacteroides genus-specific rpoB PCR and B. fragilis species-specific rpoB PCR allowed Bacteroides spp. to be differentiated from Porphyromonas and Prevotella spp., and also allowed B. fragilis to be differentiated from other non-fragilisBacteroides spp. included in the present study.

Genetic diversity of Legionella pneumophila inferred from rpoB and dotA sequences.

This study characterised the population structure of Legionella pneumophila by comparing the rpoB (300-bp) and dotA (360-bp) sequences of 267 isolates (18 reference strains, 149 Korean isolates and 100 Japanese isolates). In addition to the six clonal subgroups established previously, four subgroups, P-V to P-VIII, were identified. Subgroupings based on rpoB and dotA sequences were found to correlate with the source of the isolates, and this data may be useful for future epidemiological studies. Fourteen (five Korean and nine Japanese) isolates showed incongruent subgroupings in the rpoB and dotA trees, suggesting that genetic exchange among subgroups, and even among subspecies, may occur frequently in nature.

Depressive symptoms of type 2 diabetics treated with insulin compared to diabetics taking oral anti-diabetic drugs: a Korean study.

OBJECTIVE: The purpose of this study was to examine the depressive symptoms of type 2 diabetic patients who were treated with insulin compared to those diabetics treated with oral anti-diabetic drugs in Korea. METHODS: A total 204 outpatients with type 2 diabetes were invited to complete a questionnaire using the Beck depression inventory (BDI) to measure depressive symptoms. Age, gender, body mass index, serum lipid profile, and a social history including marital status, occupation and educational background were also assessed. The presence of diabetic complications was evaluated by examining the patients' medical records. Diabetic patients who were not treated with anti-diabetic drugs were excluded. All the study subjects were classified into two groups based on their mode of therapy: the oral drug group and insulin group. The insulin group included patients treated with insulin-oral drug combinations as well as those treated solely with insulin. RESULTS: Overall, 32.4% of our diabetic subjects showed depressive symptoms with the criterion being a BDI score > or = 16. Compared to the oral drug group, the insulin group showed a significantly higher frequency of depressive symptoms (insulin group, 48.0%; oral drug group, 27.3%; p<0.01) and higher BDI scores (insulin group, 16.6+/-10.7; oral drug group, 12.6+/-8.7; p<0.01). Moreover, after an adjustment for social factors, the degree of hyperglycemia and the presence of diabetic complications, the insulin group showed a significantly higher frequency of depression (odds ratio 4.38, 95% CI 1.66-11.6, p=0.003), compared to the oral drug group. CONCLUSIONS: The data showed that insulin treatment is related to the presence of depressive symptoms, and the importance of more careful psychological support of Korean insulin-treated type 2 diabetic patients is strongly suggested.

Transcriptomic analysis of colistin-susceptible and colistin-resistant isolates identifies genes associated with colistin resistance in Acinetobacter baumannii.

The emergence of colistin-resistant Acinetobacter baumannii is concerning, as colistin is often regarded as the last option for treating multidrug-resistant (MDR) A. baumannii infections. Using mRNA sequencing, we compared whole transcriptomes of colistin-susceptible and colistin-resistant A. baumannii strains, with the aim of identifying genes involved in colistin resistance. A clinical colistin-susceptible strain (06AC-179) and a colistin-resistant strain (07AC-052) were analysed in this study. In addition, a colistin-resistant mutant (06AC-179-R1) derived from 06AC-179 was also included in this study. High throughput mRNA sequencing was performed with an Illumina HiSeq TM 2000. In total, six genes were identified as associated with colistin resistance in A. baumannii. These six genes encode PmrAB two-component regulatory enzymes, PmrC (a lipid A phosphoethanolamine transferase), a glycosyltransferase, a poly-ß-1,6-N-acetylglucosamine deacetylase, and a putative membrane protein. Matrix-assisted laser desorption/ionization time of flight mass spectrometry revealed that all three colistin-resistant strains used in this study had modified lipid A structure by addition of phosphoethanolamine. As genes found in our results are all associated with either lipopolysaccharide biosynthesis or electrostatic changes in the bacterial cell membrane, lipopolysaccharide modification might be one of the principal modes of acquisition of colistin resistance in some A. baumannii strains.

Phylogenetic re-evaluation of Trametes consors based on mitochondrial small subunit ribosomal DNA sequences.

Mitochondrial small subunit ribosomal DNAs of Cerrena unicolor and Trametes consors were sequenced and compared with those of known mushroom taxa. Trametes consors is a species recently transferred from Irpex, and Cerrena is a genus closely related to Trametes. The present phylogenetic tree showed that Cerrena unicolor and Trametes consors clustered together and made an independent lineage from the Trametes group. A new combination, Cerrena consors (Berk.) Ko and Jung, comb nov., is proposed here by transferring Trametes consors into Cerrena based on molecular data along with taxonomic evidence.

Phylogenetic analysis of Xylaria based on nuclear ribosomal ITS1-5. 8S-ITS2 sequences.

To elucidate phylogenetic relationships of Xylaria, nuclear ribosomal ITS1-5.8S-ITS2 regions from 22 strains of 18 species were sequenced. Members of Xylaria formed a monophyletic group and proved to be phylogenetically homogeneous except for Xylaria cubensis. Species of the section Xylorugosa were divided into three groups and X. cubensis belonging to the section Xyloglossa developed an independent lineage from the section Xylorugosa. Groupings were partially congruent with the morphological taxonomy. The stromal structure, ascal apex, ectostromal surface, perithecial structure, stipe differentiation and the germ slit of ascospores were phylogenetically significant characters in grouping Xylaria.

Cell type specific and glucose responsive expression of interleukin-4 by using insulin promoter and water soluble lipopolymer.

For gene therapy, tissue targeting of gene delivery systems is required for the maximum efficiency. In this study, we constructed pRIP-IL4 in which the expression of interleukin-4 (IL-4) was driven by the rat insulin promoter. WSLP-pRIP-IL4 complex was characterized by pancreas beta-cell specific and glucose responsive expression of IL-4. pRIP-IL4 was completely retarded at a 6:1 or higher N/P (nitrogen atom of WSLP/phosphate of plasmid) ratio in 1% agarose gel. In addition, WSLP protected plasmid DNA from DNase I for more than 1 h. In cytotoxicity assay, WSLP showed less cytotoxicity than PEI (25000 Da) to mouse insulinoma (MIN6) cells. ELISA showed that pRIP-IL4 expressed much higher levels of IL-4 in MIN6 cells than in NIH3T3 cells. The expression level of IL-4 by pRIP-IL4 increased with increasing concentration of glucose. Also, IL-4 was expressed in a dose-dependent manner. This WSLP-pRIP-IL4 system will be useful in the development of a pancreas specific expression system for the prevention of diabetes without systemic side effects.

Clinical heterogeneity of insulin dependent diabetes mellitus in Korea.

This study was undertaken to find out how many current Korean patients with insulin dependent diabetes mellitus (IDDM) had a previous history of non-insulin requiring phase. Fasting serum C-peptide levels were measured in the 2300 diabetic patients during the visit to the Asan Medical Center, Seoul, Korea. Fifty-nine patients showed fasting serum C-peptide levels below 0.13 nmol/l. These 59 patients were classified further into two groups according to their history of insulin requirement: group A who required insulin within 1 year after diagnosis or presented initially as diabetic ketoacidosis and group B who had non-insulin requiring phase at least for 1 year (median: 5 years; range: 1-23 years). Twenty-six patients (44%) were classified into group A and 27 patients (46%) into group B. Median age of onset was 26 years (range: 10-50 years) and 45 years (range: 23-73 years) in groups A and B, respectively (P < 0.001). While the two groups had similar values in the current and maximum body mass indices, sex ratio and the prevalence of islet cell antibodies, 58% of the group A and 7% of the group B patients had histories of diabetic ketoacidosis. These results suggest a clinical heterogeneity in patients with IDDM in Korea.